Effects of sucrose on starch accumulation and rate of photosynthesis in Rosa cultured in vitro
ABSTRACT Shootlets of Rosa multiflora L. cv. Montse were cultured in vitro with four different levels of sucrose (0, 1, 3 and 5%). Chloroplasts of shootlets grown in a medium without sucrose contained numerous, large plastoglobuli and were lacking in starch granules. The size and number of starch granules increased with the level of sucrose in the culture medium. Starch content in leaves of shootlets grown with 5% sucrose was higher (ca 1, 3%) than those grown with 3% (ca 0, 45%) and 1% sucrose (ca 0, 27%). Starch might be used by the in vitro shootlets during the acclimation period.
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ABSTRACT: Plantlets of Alocasia amazonica were regenerated on the MS medium supplemented with different concentrations (0–9%) of sucrose. An absence of sucrose in the growth medium induced generation of leaves, however, it decreased multiplication. On contrary, sucrose supply of 6% or 9% enhanced multiplication but hampered photoautotrophic growth (generation of leaves). Increasing sucrose supply also increased sugars and starch content and number of stomata and decreased water potential and size of stomata during in vitro growth period. During exvitro acclimatization, shoot length, root length, leaf number and root number of Alocasia plantlets grown with 3% sucrose, were found to be better among the other studied sucrose concentrations. Under exvitro acclimatization, number of stomata, contents of various carbohydrates in the leaves were increased but size of stomata decreased with increasing sucrose supply during invitro growth period. Moreover, water potential of leaves of plantlets, which have been grown with a sucrose concentration other than 3%, was decreased. During invitro growth, net CO2 assimilation rate (PN), transpiration (E), stomatal conductance (gs) and variable fluorescence to maximum fluorescence ratio (Fv/Fm) were unaffected, however, during acclimatization these were changed and maximum PN, E, and gs were observed in the plantlets micropropagated with 3% sucrose. Fv/Fm was decreased severely in the plantlets micropropagated with 6% sucrose during acclimatization. Thus a sucrose concentration of 3% in the medium is appeared to be better among studied concentrations for both invitro growth and exvitro acclimatization of A.amazonica plantlets.Plant Cell Tissue and Organ Culture 01/2009; 96(3):307-315. · 3.63 Impact Factor
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ABSTRACT: To study the effect of sucrose on the sink-source relationship in in vitro-grown plants, Cistus incanus seedlings and plantlets were grown horizontally in a two-compartment Petri dish (split dish), with the root system in one compartment and the shoot in the other. Shoots and roots were exposed to different sucrose concentrations (0–30 g dm−3), two irradiance levels (25 and 160 µmol m−2s−1) and the presence or absence of a minimum medium containing minerals and vitamins (M medium). Root and shoot biomass of the seedlings was enhanced by an increase in irradiance when the growth medium was not supplemented with sucrose indicating the role of photosynthesis in biomass production. When sucrose was added to either organ growth was enhanced as well. In the presence of sucrose in the root compartment, sucrose applied to the shoot compartment enhanced growth of both organs under low irradiance, while under high irradiance, sucrose had no further additive effect. In the absence of sucrose in the root compartment, the enhancement of root biomass by sucrose added to the shoot compartment was lower under high irradiance than under low irradiance. The response of Cistus plantlets to sucrose and irradiance differed from that of seedlings, probably reflecting a greater susceptibility of the plantlets to sucrose feedback inhibition on photosynthesis and biomass accumulation. The decrease in root and shoot growth when M medium was added to the shoot compartment and the relatively better growth of these organs when the roots were supplied with minerals and the shoot with sucrose, indicate that growth of the two organs in our experimental set-up was regulated by opposing fluxes of C and nutrients.Biologia Plantarum 01/2009; 53(3):415-421. · 1.69 Impact Factor
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ABSTRACT: In vitro physiology and carbon metabolism can be affected by the sink–source relationship. The effect of different sucrose concentrations (10, 30, and 50g L−1), light intensities (80 and 150μmolm−2s−1), and CO2 levels (375 and 1,200μmolmol−1) were tested during plantain micropropagation in temporary immersion bioreactors. Activities of pyruvate kinase, phosphoenol pyruvate carboxylase, and the photosynthesis rate were recorded. From the morphological and practical point of view, the best results were obtained when plants were cultured with 30g L−1 sucrose, 80μmolm−2s−1 light intensity, and 1,200μmolmol−1 CO2 concentration. This treatment improved leaf and root development, reduced respiration during in vitro culture, and increased starch level at the end of the hardening phase. In addition to that, the number of competent plants was increased from 80.0% to 91.0% at the end of the in vitro phase and the survival percentage from 95.71% to 99.80% during ex vitro hardening.In Vitro Cellular & Developmental Biology - Plant 01/2010; 46(1):89-94. · 1.14 Impact Factor